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net: cdc_ncm: refactoring for tx multiplexing
Adding multiplexed NDP support to cdc_ncm_fill_tx_frame, allowing transmissions of multiple independent sessions within the same NTB. Refactoring the code quite a bit to avoid having to store copies of multiple NDPs being prepared for tx. The old code would still reserve enough room for a maximum sized NDP in the skb so we might as well keep them in the skb while they are being prepared. Signed-off-by: Bjørn Mork <bjorn@mork.no> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Bjørn Mork
David S. Miller
parent
ff06ab13a4
commit
c78b7c5866
@ -88,14 +88,11 @@
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(sizeof(struct usb_cdc_ncm_nth16) + sizeof(struct usb_cdc_ncm_ndp16) + \
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(CDC_NCM_DPT_DATAGRAMS_MAX + 1) * sizeof(struct usb_cdc_ncm_dpe16))
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struct cdc_ncm_data {
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struct usb_cdc_ncm_nth16 nth16;
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struct usb_cdc_ncm_ndp16 ndp16;
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struct usb_cdc_ncm_dpe16 dpe16[CDC_NCM_DPT_DATAGRAMS_MAX + 1];
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};
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#define CDC_NCM_NDP_SIZE \
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(sizeof(struct usb_cdc_ncm_ndp16) + \
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(CDC_NCM_DPT_DATAGRAMS_MAX + 1) * sizeof(struct usb_cdc_ncm_dpe16))
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struct cdc_ncm_ctx {
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struct cdc_ncm_data tx_ncm;
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struct usb_cdc_ncm_ntb_parameters ncm_parm;
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struct hrtimer tx_timer;
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struct tasklet_struct bh;
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@ -117,13 +114,12 @@ struct cdc_ncm_ctx {
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struct sk_buff *tx_curr_skb;
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struct sk_buff *tx_rem_skb;
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__le32 tx_rem_sign;
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spinlock_t mtx;
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atomic_t stop;
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u32 tx_timer_pending;
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u32 tx_curr_offset;
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u32 tx_curr_last_offset;
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u32 tx_curr_frame_num;
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u32 rx_speed;
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u32 tx_speed;
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@ -658,51 +654,75 @@ static int cdc_ncm_bind(struct usbnet *dev, struct usb_interface *intf)
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return ret;
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}
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static void cdc_ncm_zero_fill(u8 *ptr, u32 first, u32 end, u32 max)
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static void cdc_ncm_align_tail(struct sk_buff *skb, size_t modulus, size_t remainder, size_t max)
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{
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if (first >= max)
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return;
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if (first >= end)
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return;
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if (end > max)
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end = max;
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memset(ptr + first, 0, end - first);
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size_t align = ALIGN(skb->len, modulus) - skb->len + remainder;
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if (skb->len + align > max)
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align = max - skb->len;
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if (align && skb_tailroom(skb) >= align)
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memset(skb_put(skb, align), 0, align);
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}
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/* return a pointer to a valid struct usb_cdc_ncm_ndp16 of type sign, possibly
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* allocating a new one within skb
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*/
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static struct usb_cdc_ncm_ndp16 *cdc_ncm_ndp(struct cdc_ncm_ctx *ctx, struct sk_buff *skb, __le32 sign, size_t reserve)
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{
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struct usb_cdc_ncm_ndp16 *ndp16 = NULL;
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struct usb_cdc_ncm_nth16 *nth16 = (void *)skb->data;
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size_t ndpoffset = le16_to_cpu(nth16->wNdpIndex);
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/* follow the chain of NDPs, looking for a match */
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while (ndpoffset) {
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ndp16 = (struct usb_cdc_ncm_ndp16 *)(skb->data + ndpoffset);
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if (ndp16->dwSignature == sign)
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return ndp16;
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ndpoffset = le16_to_cpu(ndp16->wNextNdpIndex);
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}
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/* align new NDP */
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cdc_ncm_align_tail(skb, ctx->tx_ndp_modulus, 0, ctx->tx_max);
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/* verify that there is room for the NDP and the datagram (reserve) */
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if ((ctx->tx_max - skb->len - reserve) < CDC_NCM_NDP_SIZE)
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return NULL;
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/* link to it */
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if (ndp16)
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ndp16->wNextNdpIndex = cpu_to_le16(skb->len);
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else
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nth16->wNdpIndex = cpu_to_le16(skb->len);
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/* push a new empty NDP */
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ndp16 = (struct usb_cdc_ncm_ndp16 *)memset(skb_put(skb, CDC_NCM_NDP_SIZE), 0, CDC_NCM_NDP_SIZE);
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ndp16->dwSignature = sign;
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ndp16->wLength = cpu_to_le16(sizeof(struct usb_cdc_ncm_ndp16) + sizeof(struct usb_cdc_ncm_dpe16));
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return ndp16;
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}
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static struct sk_buff *
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cdc_ncm_fill_tx_frame(struct cdc_ncm_ctx *ctx, struct sk_buff *skb)
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cdc_ncm_fill_tx_frame(struct cdc_ncm_ctx *ctx, struct sk_buff *skb, __le32 sign)
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{
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struct usb_cdc_ncm_nth16 *nth16;
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struct usb_cdc_ncm_ndp16 *ndp16;
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struct sk_buff *skb_out;
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u32 rem;
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u32 offset;
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u32 last_offset;
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u16 n = 0, index;
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u16 n = 0, index, ndplen;
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u8 ready2send = 0;
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/* if there is a remaining skb, it gets priority */
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if (skb != NULL)
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if (skb != NULL) {
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swap(skb, ctx->tx_rem_skb);
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else
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swap(sign, ctx->tx_rem_sign);
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} else {
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ready2send = 1;
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/*
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* +----------------+
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* | skb_out |
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* +----------------+
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* ^ offset
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* ^ last_offset
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*/
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}
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/* check if we are resuming an OUT skb */
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if (ctx->tx_curr_skb != NULL) {
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/* pop variables */
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skb_out = ctx->tx_curr_skb;
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offset = ctx->tx_curr_offset;
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last_offset = ctx->tx_curr_last_offset;
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n = ctx->tx_curr_frame_num;
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skb_out = ctx->tx_curr_skb;
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} else {
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/* reset variables */
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/* allocate a new OUT skb */
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if (!skb_out) {
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skb_out = alloc_skb((ctx->tx_max + 1), GFP_ATOMIC);
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if (skb_out == NULL) {
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if (skb != NULL) {
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@ -711,35 +731,21 @@ cdc_ncm_fill_tx_frame(struct cdc_ncm_ctx *ctx, struct sk_buff *skb)
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}
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goto exit_no_skb;
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}
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/* fill out the initial 16-bit NTB header */
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nth16 = (struct usb_cdc_ncm_nth16 *)memset(skb_put(skb_out, sizeof(struct usb_cdc_ncm_nth16)), 0, sizeof(struct usb_cdc_ncm_nth16));
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nth16->dwSignature = cpu_to_le32(USB_CDC_NCM_NTH16_SIGN);
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nth16->wHeaderLength = cpu_to_le16(sizeof(struct usb_cdc_ncm_nth16));
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nth16->wSequence = cpu_to_le16(ctx->tx_seq++);
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/* make room for NTH and NDP */
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offset = ALIGN(sizeof(struct usb_cdc_ncm_nth16),
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ctx->tx_ndp_modulus) +
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sizeof(struct usb_cdc_ncm_ndp16) +
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(ctx->tx_max_datagrams + 1) *
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sizeof(struct usb_cdc_ncm_dpe16);
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/* store last valid offset before alignment */
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last_offset = offset;
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/* align first Datagram offset correctly */
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offset = ALIGN(offset, ctx->tx_modulus) + ctx->tx_remainder;
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/* zero buffer till the first IP datagram */
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cdc_ncm_zero_fill(skb_out->data, 0, offset, offset);
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n = 0;
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/* count total number of frames in this NTB */
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ctx->tx_curr_frame_num = 0;
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}
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for (; n < ctx->tx_max_datagrams; n++) {
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/* check if end of transmit buffer is reached */
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if (offset >= ctx->tx_max) {
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ready2send = 1;
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break;
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}
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/* compute maximum buffer size */
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rem = ctx->tx_max - offset;
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for (n = ctx->tx_curr_frame_num; n < ctx->tx_max_datagrams; n++) {
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/* send any remaining skb first */
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if (skb == NULL) {
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skb = ctx->tx_rem_skb;
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sign = ctx->tx_rem_sign;
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ctx->tx_rem_skb = NULL;
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/* check for end of skb */
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@ -747,7 +753,14 @@ cdc_ncm_fill_tx_frame(struct cdc_ncm_ctx *ctx, struct sk_buff *skb)
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break;
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}
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if (skb->len > rem) {
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/* get the appropriate NDP for this skb */
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ndp16 = cdc_ncm_ndp(ctx, skb_out, sign, skb->len + ctx->tx_modulus + ctx->tx_remainder);
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/* align beginning of next frame */
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cdc_ncm_align_tail(skb_out, ctx->tx_modulus, ctx->tx_remainder, ctx->tx_max);
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/* check if we had enough room left for both NDP and frame */
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if (!ndp16 || skb_out->len + skb->len > ctx->tx_max) {
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if (n == 0) {
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/* won't fit, MTU problem? */
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dev_kfree_skb_any(skb);
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@ -760,31 +773,30 @@ cdc_ncm_fill_tx_frame(struct cdc_ncm_ctx *ctx, struct sk_buff *skb)
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ctx->netdev->stats.tx_dropped++;
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}
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ctx->tx_rem_skb = skb;
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ctx->tx_rem_sign = sign;
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skb = NULL;
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ready2send = 1;
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}
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break;
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}
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memcpy(((u8 *)skb_out->data) + offset, skb->data, skb->len);
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/* calculate frame number withing this NDP */
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ndplen = le16_to_cpu(ndp16->wLength);
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index = (ndplen - sizeof(struct usb_cdc_ncm_ndp16)) / sizeof(struct usb_cdc_ncm_dpe16) - 1;
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ctx->tx_ncm.dpe16[n].wDatagramLength = cpu_to_le16(skb->len);
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ctx->tx_ncm.dpe16[n].wDatagramIndex = cpu_to_le16(offset);
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/* update offset */
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offset += skb->len;
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/* store last valid offset before alignment */
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last_offset = offset;
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/* align offset correctly */
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offset = ALIGN(offset, ctx->tx_modulus) + ctx->tx_remainder;
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/* zero padding */
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cdc_ncm_zero_fill(skb_out->data, last_offset, offset,
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ctx->tx_max);
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/* OK, add this skb */
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ndp16->dpe16[index].wDatagramLength = cpu_to_le16(skb->len);
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ndp16->dpe16[index].wDatagramIndex = cpu_to_le16(skb_out->len);
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ndp16->wLength = cpu_to_le16(ndplen + sizeof(struct usb_cdc_ncm_dpe16));
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memcpy(skb_put(skb_out, skb->len), skb->data, skb->len);
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dev_kfree_skb_any(skb);
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skb = NULL;
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/* send now if this NDP is full */
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if (index >= CDC_NCM_DPT_DATAGRAMS_MAX) {
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ready2send = 1;
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break;
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}
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}
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/* free up any dangling skb */
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@ -800,16 +812,12 @@ cdc_ncm_fill_tx_frame(struct cdc_ncm_ctx *ctx, struct sk_buff *skb)
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/* wait for more frames */
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/* push variables */
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ctx->tx_curr_skb = skb_out;
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ctx->tx_curr_offset = offset;
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ctx->tx_curr_last_offset = last_offset;
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goto exit_no_skb;
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} else if ((n < ctx->tx_max_datagrams) && (ready2send == 0)) {
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/* wait for more frames */
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/* push variables */
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ctx->tx_curr_skb = skb_out;
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ctx->tx_curr_offset = offset;
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ctx->tx_curr_last_offset = last_offset;
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/* set the pending count */
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if (n < CDC_NCM_RESTART_TIMER_DATAGRAM_CNT)
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ctx->tx_timer_pending = CDC_NCM_TIMER_PENDING_CNT;
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@ -820,75 +828,24 @@ cdc_ncm_fill_tx_frame(struct cdc_ncm_ctx *ctx, struct sk_buff *skb)
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/* variables will be reset at next call */
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}
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/* check for overflow */
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if (last_offset > ctx->tx_max)
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last_offset = ctx->tx_max;
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/* revert offset */
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offset = last_offset;
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/*
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* If collected data size is less or equal CDC_NCM_MIN_TX_PKT bytes,
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* we send buffers as it is. If we get more data, it would be more
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* efficient for USB HS mobile device with DMA engine to receive a full
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* size NTB, than canceling DMA transfer and receiving a short packet.
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*/
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if (offset > CDC_NCM_MIN_TX_PKT)
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offset = ctx->tx_max;
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if (skb_out->len > CDC_NCM_MIN_TX_PKT)
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/* final zero padding */
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memset(skb_put(skb_out, ctx->tx_max - skb_out->len), 0, ctx->tx_max - skb_out->len);
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/* final zero padding */
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cdc_ncm_zero_fill(skb_out->data, last_offset, offset, ctx->tx_max);
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/* do we need to prevent a ZLP? */
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if (((skb_out->len % le16_to_cpu(ctx->out_ep->desc.wMaxPacketSize)) == 0) &&
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(skb_out->len < le32_to_cpu(ctx->ncm_parm.dwNtbOutMaxSize)) && skb_tailroom(skb_out))
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*skb_put(skb_out, 1) = 0; /* force short packet */
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/* store last offset */
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last_offset = offset;
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if (((last_offset < ctx->tx_max) && ((last_offset %
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le16_to_cpu(ctx->out_ep->desc.wMaxPacketSize)) == 0)) ||
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(((last_offset == ctx->tx_max) && ((ctx->tx_max %
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le16_to_cpu(ctx->out_ep->desc.wMaxPacketSize)) == 0)) &&
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(ctx->tx_max < le32_to_cpu(ctx->ncm_parm.dwNtbOutMaxSize)))) {
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/* force short packet */
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*(((u8 *)skb_out->data) + last_offset) = 0;
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last_offset++;
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}
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/* zero the rest of the DPEs plus the last NULL entry */
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for (; n <= CDC_NCM_DPT_DATAGRAMS_MAX; n++) {
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ctx->tx_ncm.dpe16[n].wDatagramLength = 0;
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ctx->tx_ncm.dpe16[n].wDatagramIndex = 0;
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}
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/* fill out 16-bit NTB header */
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ctx->tx_ncm.nth16.dwSignature = cpu_to_le32(USB_CDC_NCM_NTH16_SIGN);
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ctx->tx_ncm.nth16.wHeaderLength =
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cpu_to_le16(sizeof(ctx->tx_ncm.nth16));
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ctx->tx_ncm.nth16.wSequence = cpu_to_le16(ctx->tx_seq);
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ctx->tx_ncm.nth16.wBlockLength = cpu_to_le16(last_offset);
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index = ALIGN(sizeof(struct usb_cdc_ncm_nth16), ctx->tx_ndp_modulus);
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ctx->tx_ncm.nth16.wNdpIndex = cpu_to_le16(index);
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memcpy(skb_out->data, &(ctx->tx_ncm.nth16), sizeof(ctx->tx_ncm.nth16));
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ctx->tx_seq++;
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/* fill out 16-bit NDP table */
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ctx->tx_ncm.ndp16.dwSignature =
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cpu_to_le32(USB_CDC_NCM_NDP16_NOCRC_SIGN);
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rem = sizeof(ctx->tx_ncm.ndp16) + ((ctx->tx_curr_frame_num + 1) *
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sizeof(struct usb_cdc_ncm_dpe16));
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ctx->tx_ncm.ndp16.wLength = cpu_to_le16(rem);
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ctx->tx_ncm.ndp16.wNextNdpIndex = 0; /* reserved */
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memcpy(((u8 *)skb_out->data) + index,
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&(ctx->tx_ncm.ndp16),
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sizeof(ctx->tx_ncm.ndp16));
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memcpy(((u8 *)skb_out->data) + index + sizeof(ctx->tx_ncm.ndp16),
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&(ctx->tx_ncm.dpe16),
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(ctx->tx_curr_frame_num + 1) *
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sizeof(struct usb_cdc_ncm_dpe16));
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/* set frame length */
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skb_put(skb_out, last_offset);
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/* set final frame length */
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nth16 = (struct usb_cdc_ncm_nth16 *)skb_out->data;
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nth16->wBlockLength = cpu_to_le16(skb_out->len);
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/* return skb */
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ctx->tx_curr_skb = NULL;
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@ -955,7 +912,7 @@ cdc_ncm_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
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goto error;
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spin_lock_bh(&ctx->mtx);
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skb_out = cdc_ncm_fill_tx_frame(ctx, skb);
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skb_out = cdc_ncm_fill_tx_frame(ctx, skb, cpu_to_le32(USB_CDC_NCM_NDP16_NOCRC_SIGN));
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spin_unlock_bh(&ctx->mtx);
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return skb_out;
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